When the gang take part in a student-teacher exchange program, Zack becomes principal, Kelly a History teacher and Screech and Lisa the gym teachers. However, when Zack, Screech and Kelly clash over an exam, friendships are tested.
The gang produce a television show for Communications class, with the sauce Screech makes during the cookery segment proving a hit. They decide to market it, and Screech gains a girlfriend, but he refuses to believe she is using him.
When Lisa receives word that a recruiter from FIT wants to interview her, the gang help her put on a fashion show at The Max. However, the close working conditions mean Zack and Lisa grow close, leaving Screech brokenhearted and bitter.
The gang create a teen line, designed to help students with their problems. After calling, a girl named Melissa is asked out on a date by Zack, but when he discovers she is in a wheelchair, he finds it difficult to accept.
As the annual masquerade ball approaches, Zack and Slater make a bet about who can kiss Tori first. However, when she discovers their scheme, she decides to get revenge, while Screech's love letters to Lisa cause all manner of mix ups.
After rigging a radio competition, Zack has the chance to win a trip to Hawaii, but his plans are scuppered when he is sent to detention for the day and his attempts to get the gang to help result in them being sent to detention as well.
Slater is horrified when his girlfriend from Germany arrives at Bayside as a new student. Zack helps hide the relationship from Jessie, but it is only a matter of time before she finds out, and Slater must figure out where his heart lies.
Zack appears to have negotiated a great deal on class rings for the senior class, but it turns out he has been scammed. While he plots revenge, a misguided bet between Tori and Lisa leads to Screech falling for Tori.
The school fights over how to spend the money that an alumni has left the school. Zack, Slater, Screech, Ox and the rest of the guys want the money for boys' sports while Lisa, Tori, Ginger and the girls want it for girl's sports. So Mr. Belding decides to settle the conflict by having a sports competition between the boys' blue team and the girls' red team. But Zack resorts to unethical tactics when he sabotages the girls' oven during the bake-off contest, and when the girls find out, they plan their revenge, leading to an all-out war between the sexes.
In order to go on a ski trip, Zack and Slater trick Mr. Tuttle into thinking Mr. Belding is against him, prompting a strike. However, their plan is so successful that it could cause the annual Academic Bowl to be canceled.
Zack agrees to produce Bayside's video yearbook, but betrays everyone's trust by creating a dating tape using footage of female students in order to make enough money to buy a car. When the others see the dating tape, they plot revenge.
The gang forgets Screech's birthday and decide to throw him a surprise party in Mr. Belding's office. However, after being made Hall Monitor, Screech gets his revenge by sending them to detention, jeopardizing the party.
The school puts on a hip hop version of Snow White and the Seven Dwarfs, with Zack and Jessie as the leads. However, when they seem to develop feelings for each other, they risk ruining both the play and their relationships.
In order to avoid a Physics test, the gang throw a baby shower for Mr. Belding's wife, Becky. When they are leaving the school, however, an earthquake strikes, trapping Zack and Tori in the faculty elevator with Becky, who goes into labor.
The senior class want to leave a gift to Bayside's future students and suggest a contest to come up with a new school song. However, Zack decides to rig the competition in his favor in order to be remembered for more than just bad behavior.
As graduation approaches, Zack learns that he is just one credit short of graduating. Desperate to get extra credit, he joins Bayside's ballet company, and when illness strikes some of the other cast members, he calls on the gang for help.